1. Field of the Invention
The present invention is concerned with the drying of grain in the usual bins used just for storage of grain. Grain when it is initially harvested usually is too moist to safely store in confined bins without a preliminary drying of the grain. It is a principal feature of this invention to provide grain drying mechanisms in the storage bins so that storage can commence immediately after harvesting or at any time even if the grain is too moist for the usual storage practices. Applicant has a conversion device to cause a storage chamber to become in fact a dual purpose chamber of storing and drying. Others previously have utilized storage bins to accept moist grain but they were primarily concerned with uneven drying and employed methods for recirculating, agitating or stirring the grain in the bin. Some earlier bin drying devices provided for the circulation of the grain within the bin by removing a portion of the grain from the bottom of a column of grain within the bin and reapplying it to the top of that same column. At certain times hot air would be delivered upwardly through the column of moving grain and at other times atmospheric air would be sent upwardly through the column of grain. These hot and atmospheric air currents did not as a rule act in unison nor could most of them be used together because of the physical structure of the devices. In still other prior devices perforated floors have been utilized to permit the passage of air currents. Some of these floors were conical in shape to hopefully cause the grain to spread over the full area of the bin by gravity. Many of the prior devices utilized auger sweeps for both distribution of grain and removal of grain. Applicant utilizes columns of grain within the bin to effect drying of grain. In applicants device moist grain is delivered into the top of a bin and in a first or upper chamber a column of grain is subjected to hot air and in a second or lower chamber located directly beneath the first chamber a second column of grain is simultaneously subjected to cool air. Thereafter grain is removed from a sub-chamber within the bin when the grain has been completely dried. Thus the grain, entering moist at the top makes one pass through the entire bin from top to bottom and is then delivered out of the bin in a dry cool condition. Both the hot air and cool air simultaneously pass upwardly through the columns of grain where the used air is exhausted out an opening in the top spaced apart from the moist grain inlet. Because of the two vertically spaced apart perforated floors, the cool air passing up through the column of grain in the lower chamber is permitted to mix with the incoming hot air for upward movement through the column of grain in the upper chamber. The grain moving down from the upper column is quite warm so that it acts to heat up the initially cool air which was delivered to the bottom of the lower column but which is now moving upwardly into the bottom of the uppermost column of grain. It is this entire system of operation accompanied by special auger sweep drive means that applicant has developed.
2. Description of the Prior Art
Extensive searches of the prior art have produced a variety of patents showing grain storage bins and grain drying bins with various means for circulating or agitating the grain within the bin at a time when the grain therein was subjected to drying processes.
The very old U.S. Pat. No. 765,795 to Smith shows the admission of heat into a column of grain at a position approximately midway of the height of the column.
The U.S. Pat. No. 3,156,541 to Kalke shows a grain storage bin with means for effecting stirring of the grain by a vertical auger depending into a column of grain in the bin.
The Sukup U.S. Pat. Nos. 3,198,493 and 3,272,480 disclose an auger means disposed generally vertically but swingable throughout an arcuate range for stirring or agitating the grain in the bin to more readily permit the passage therethrough of hot air or the like. This appears to be an improvement over the Kalke patent already discussed. Sukup also discloses a radially disposed auger for effecting a spreading or a distribution of the grain within a bin.
The Batterton et al U.S. Pat. No. 3,440,734 is similar to Smith U.S. Pat. No. 765,795 in that it discloses the delivery of heat into a column of grain being dried at a position intermediate the top and bottom of the column.
The Francis U.S. Pat. No. 3,449,840 shows a grain drying apparatus in which incoming grain is delivered to a trough member having radially disposed conveyor means therein. The stream of grain entering this trough member is distributed radially on the trailing side of the trough sweep while another conveyor on the trough is removing grain from the lead side of the sweeping trough. Thus the Francis principle is to maintain a very shallow layer of grain which is subjected to heat during one revolution of the trough at which time the dried grain is removed.
The U.S. Patents to Sietmann No. 3,479,748; Sietmann No. 3,501,845; and Sietmann et al No. 3,849,901 all show grain bins in which drying of the grain is the goal to be attained. All of these devices employ conically shaped perforated floors disposed just beneath a conical top to temporarily hold the incoming grain while it is subjected to hot air moving upwardly therethrough. The conical floors are ostensibly used to cause grain distribution but this then necessitates the use of complicated dams to obtain even a short column of grain and they are not commensurate to applicant's flat floors with substantial full cylindrical columns of grain.
The Shivvers U.S. Pat. Nos. 3,563,399; 3,765,547; and 3,765,548 all show a bin with a central auger disposed vertically therein for recirculating the bin's grain. When the grain moving gradually downwardly reaches the bottom it is then taken upwardly by the central auger and deposited onto the top of the column. During this recirculation process the grain is subjected first to hot air and then at a different time this same column of grain is subjected to atmospheric air. At no time are the hot air and atmospheric air currents moving together as in applicant's device.
The Lambert, Jr. U.S. Pat. No. 3,755,917 is similar in construction to the Francis patent previously described. Here the incoming grain is delivered to a very narrow but elongated box-like member called a duct and it is within this narrow duct that the grain is preliminarily dried.
The Patterson U.S. Pat. No. 3,800,964 shows and describes an auger sweep in a grain drying bin which is equipped with spaced apart cogs on the helical edge of the auger so that the cogs define a segmented spiroid rim. This construction is supposed to enhance rotation of the sweep about its center.
The Rutten et al U.S. Pat. No. 4,029,219 shows a grain storage bin but is concerned only with a clutch means disposed at a location outside the bin through which the drive to sweep auger is delivered.
From the numerous patents discussed and described very briefly above it is obvious that this is indeed a crowded art. In no instance did we find an entire drying system of superposed full cylindrical columns of grain for effecting the drying of moist grain. In applicant's device grain is delivered to and into the top of a bin where it is subjected to a controlled descent through a first upper column and thence through a second lower column to a sub-chamber where it is discharged. Applicant's grain is dried without going through a recirculating cycle or without auxiliary agitation. In applicant's device the moist grain is first subjected to hot air in an upper column and then subjected to cold air in a second lower column. The incoming hot air and the exhausting air from the coolant chamber is admixed for passing through the first or upper column of grain. After the grain moves downwardly through these superposed separate columns of grain it is discharged from a sub-chamber beneath the second lower column of grain.
Further, although there are many that have used radially disposed auger sweep members we have not been able to find that anyone has utilized an auger at the outer end of the radial auger and disposed at right angles thereto for effecting drive of that sweep auger in a circular direction through a massive column of grain during drying. Thus applicant has developed an entire system for the drying of grain within an ordinary grain storage chamber. Applicant's drying system includes sweep augers which are positively driven through the bottoms of columns of grain despite the depths of the columns.